Gear:---Toss/Throw bags

Hold the bag in the hand that you plan to throw the bag with. Remove the end of the rope from the other hand and hold it firmly.
If the swimmer is being carried downstream, plan to throw the bag downstream or ahead of the swimmer. If you simply aim for the swimmer chances are the bag will land upstream or behind him or her since they will continue moving while the bag is in the air.

This is the moment of truth. You will throw the bag not the end of the rope. Be sure to hold onto a significant portion of the rope end securely. A second person can also hold the rope end, providing additional support. Throw the bag with the rope in it using an underhand motion. Don’t worry about throwing the bag downstream of the swimmer as they should be able to swim to it.
Have the swimmer take hold of the rope, not the bag!
at this point At this point the current will do the work. Both people involved in the whitewater rescue, the rescuer and the person being rescued, should just hold securely onto the rope. Your swimmer will be taken to the bank in a slow arc provided you stand still and keep a tight grip.

you can buy ready made Toss/throw bags at almost any boat marine supply store. prices range from $30 to $90 bucks.

Even nonboating folks might find this useful esp since it looks like will have a nasty flooding event once all the snow melts